Words that sound similar to the noises they describe. (Boom, splash, buzz)

Pooh-Pooh-Theory (natural sound source)

Idea that speech developed from the instinctive sounds people make in emotional circumstances. ( ohh, ahh, ouch, wow)

Social interaction source

yo-he-ho-theoryIdea that the source could be the sounds people make involved in physical efforts. (Grunts, groans, hums,..)! This idea places the development in a SOCIAL CONTEXT!) -- sounds were used in SOCIAL INTERACTION

The physical interaction source 1

Idea that physical features might have been able to support speech production.